Considerable interest has arisen in the development of nanotechnological methods for the miniaturization, printing, and fabrication of nanoscale electronic and optical devices (see, for example, references 1–3, at the end of the specification). One proprietary, commercial method is DIP PEN NANOLITHOGRAPHY™ printing (DPN™ printing) (see, for example, referenced 4–6; DIP PEN NANOLITHOGRAPHY™ and DPN™ are proprietary trademarks of NanoInk, Inc., Chicago, Ill. and are used accordingly in this specification). Several embodiments exist for this promising new nanofabrication tool, which allows one to pattern molecules and other patterning inks on a variety of surfaces using nanoscopic tips including scanning probe microscopic (SPM) tips. In one embodiment, patterning is carried out with a coated atomic force microscope (AFM) tip in a controlled fashion on the sub-100 nm to many micrometer length scale (see, for example, references 5–6). In a typical printing experiment, a commercially available AFM cantilever can be coated with ink molecules by thermal evaporation or by dip-coating procedures (see, for example, references 4 and 10). The ink molecules can be transported to a substrate, often via capillary action, by bringing the tip into contact with the surface. Chemisorption of the ink to the underlying substrate can be used as a driving force for moving the molecules from the tip to the substrate. Significant work thus far has been done, for example, with the thiol-gold combination.
Despite the advances in the field, a commercial need exists to expand the scope of nanolithographic printing, including the mechanisms which can be used to bind the patterning compound with the substrate to impart technologically useful properties, particularly electrical and optical properties for use in nanoelectronic and nanooptical devices. With improved knowledge, for example, less experimentation may be needed to solve a particular technical challenge and additional tools are available to solve particular technical challenges. For example, printing of synthetic polymeric compounds is important, as is the printing of conducting materials and conducting organic materials. These include electronically conducting and light emitting conducting polymers to form nanowires, nanoscale light emitting diodes, and nanocircuitry. Printing with use of additional interactions to drive the printing besides chemisorption, covalent bonding, or physisorption is desired. Printing on semi-conductor and insulating, dielectric substrates is desired. Better surface modification processes are desired.
U.S. Pat. No. 6,270,946 (Miller, listed assignee: Luna Innovations) discloses nonlithographic use of ionic interactions among difunctional molecules to build layers of multi-layer films. No working examples, however, are provided.